<!DOCTYPE html>
<html>
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>

    </title>
    <style>
        .box{
            width: 200px;
            height: 200px;
            background-color: red;
            border-radius: 50%;
            margin: 100px auto;
             animation: xd 0.1s infinite linear alternate;
        }
      @keyframes xd{
        from{
                transform: scale(1);
            }
            tp{
                transform: scale(2);
            }
      }
    </style>
</head>
<body>
    <div class="box"></div>
</body>
</html>